Richard Clarke, the former terrorism adviser whose revelations threaten to torpedo George Bush's re-election strategy, launched a counterattack yesterday at a White House that he said was determined to destroy him.

In a riveting television performance, Mr Clarke called on his principal critic and former employer, the national security adviser, Condoleezza Rice, to release the entire record of their emails in the months up to the September 11 terror attacks to prove his contention that the White House did not then take the threat of al-Qaida seriously.

He also agreed to Republican demands to declassify testimony he gave to the Senate two years ago - to "prove" there were no inconsistencies. "Let's take all of my emails and all the memos I sent to the national security adviser and her deputy from January 20 to September 11 and let's declassify all of them," Mr Clarke told NBC television.

Mr Clarke's bravura presentation surprised the Bush administration. The decision to stand his ground could also be destructive to Ms Rice. She has been under intense scrutiny for a week - largely for being the focus of Mr Clarke's charges that the Bush government did not see al-Qaida as a priority before September 11, but also because she refused to testify before the commission.

Yesterday, the commission's chairman, Thomas Kean, called for Ms Rice to testify in public. "We recognise there are arguments having to do with separation of powers. We think in a tragedy of this magnitude that those kind of legal arguments are probably overridden," he said. But he said he would not force the issue with a court order.

Even leading Republican figures are criticising Ms Rice's refusal to appear, saying it looked as if she had something to hide. "I think she'd be wise to testify," said Richard Perle, a former Pentagon adviser.

Further damage was inflicted yesterday in a Los Angeles Times report discrediting a prewar claim by the Bush administration that Saddam Hussein had trucks capable of dispersing dangerous substances such as anthrax. The report claimed the information came from a single discredited source and reached US intelligence agents third-hand.

In Israel, meanwhile, a parliamentary committee investigating exaggerated prewar claims over Iraqi weapons of mass destruction concluded that western agencies had dealt in speculation not facts.

The committee said claims that Saddam was expanding his armoury were based on evaluations shared among intelligence agencies in Israel, the US, Britain and elsewhere, that reinforced "dubious interpretations" of the few facts available.

But the report released yesterday by the foreign affairs and defence committee said that while there was a "serious intelligence failure" there was no evidence of deliberate deception to build a false case.